Is your schedule too packed to hit the gym? You don't have to do hours of cardio to slim down. Instead, try fitting in fitness throughout the day with these simple moves.

Watch the clock

Watch the clock

If you think you need to exercise for an hour straight most days of the week in order to lose weight and melt belly fat, think again. The key is to workout smarter, not longer. New studies show that the most effective form of exercise for adults may be fast, short, and intense types of anaerobic exercise (as contrasted with low-intensity exercise like steady walking). Moreover, other research finds that doing two or three shorter workouts (such as 15 minutes in the morning and 15 minutes at night) is just as effective as a single, longer workout, says Greta Blackburn, CPT, fitness expert based in LA and founder of a national series of boot camps called FITCAMPS.

Crank up the pace

Crank up the pace

Incorporating intervals versus exercising steadily at the same pace not only burns more calories. It also does a better job of amping your metabolism for the 24-hour period after a workout. Whether you're swimming laps, running, riding a stationary bike, or using the treadmill, you can increase the calorie burn by picking up the pace to the point where you are so out of breath that you can't even talk for 30 seconds, then slow down for one-and-a-half minutes to recover. Start with a five-minute warm up, repeat your 30-second intervals eight times, and then recover for 10 minutes.